Why can we observe solar eclipses? How are craters formed on the moon? Why are there seasons on earth? Such questions are often asked by new astronomers, but can be a bit difficult to answer.
How can abstract situations in which several bodies move and interact be explained?
Well, it’s easier than you think! These six experiments will help young people understand some of the complex principles of space science… and stay young at heart.
1. How are craters formed?
You will need: a bowl, flour, cocoa and stones or balls of different sizes.
Have you ever liked to see the moon? Its scarred surface is dominated by large pools and craters of varying sizes and shapes. But how did these craters form and why are some craters deeper or longer than others?
The following experiment aims to show what happened on the moon’s surface over millions of years.
Fill the bowl about 2-3 cm high with flour. Then sprinkle the surface with cocoa. The cocoa is only there to burst the crater, so any dark force will do.
Find an easy-to-clean floor or table and set up the sink. Then put a pebble in the flour.Congratulations – you’ve created your first crater!
Try to change the speed of the pebble by dropping it from different heights, or try throwing it carefully into a corner (but be careful not to spill flour on the ground). This allows you to see how the angle and velocity of the impact affects the shape of the crater.
Throw handfuls of small pebbles and even create chains of impact craters similar to those on the moon.
2. Measuring the Size of the Sun and Moon
You will need: a shoebox, aluminum foil, tape, a sheet of white paper, a ruler, and a pin or needle.
Although the sun is almost 150 million kilometers away and huge, you can measure its size from your living room.
You build a simple pinhole camera. From the middle of one of the short sides of the shoebox, cut a 2 x 2 cm square. Place the aluminum foil on the cutout and tape it in place.
Then pierce the sheet metal with a pin or needle. Line the inside of the opposite end of the box with white paper.
You now have a pinhole camera. Measure the length of the box from the opening to the piece of paper.
Point the foil-wrapped front towards the sun, never look directly into it!
An image of the sun appears on the sheet, which can be measured with a ruler. Using this measurement and some simple math, you can calculate the diameter of the sun:
,
diameter of the sun = image size ÷ box length x 149,600,000 km
Since 149,600,000 km is the distance from the sun and the relationship between hole size and distance is the same for both, this should give a good estimate of the Sun’s size.
You can use the same method for the moon, but change the number to 384,000 km at the end.
When you’re done, check your score to see how close you are. The bigger the box, the more accurate you will be.
3. How does rotation change the shape of planets?
You will need a stick, cards, scissors, a ruler, glue and a compass.
planets are not perfect spheres. They swell at the equator and flatten at the poles. The bigger the planet, the greater the impact.
planets get distorted this way because they rotate, and this experiment shows you how.
First you need to build a model of the planet. Cut out three circles from a piece of paper: two should be 4 cm in diameter (let’s call them A and B) and one should be 3 cm (let’s call it C).
Next, drill a hole in washers A and C large enough to seat firmly on the stick. Then punch a larger hole in B to make it easier to slide up and down the stick.
Now cut out eight cardboard strips (each approx. 1.25x30cm). Glue one end of each strip around the edge of disc A to make it look like a spider. Then put it on the stick.
Then attach C to the post about 15cm from A for reference.Finally place B on the stick under C and glue the ends of the strips around the edge so it looks like the planetary model on the right. Make sure B can move freely along the stick.
Now hold the stick in your hands and twist it. Try changing the stick’s rotation speed and see what happens. You should note that the faster you turn the stick, the more the “Planet” will inflate.
4. Measure the dimensions of the solar system
You will need cardboard, a compass, and a roll of toilet paper.
The sizes of the planets in our solar system and the distances between them can be difficult to fathom, but this experiment will help put things into perspective.
First, draw circles on pieces of cardboard using the scale radii in the table below to create your planets (don’t forget to mark them along the way).
We’ve given the Earth a 1cm radius as a starting point and left out the Sun because it would be 2.2m wide on that scale!
To show the distances between the planets, we use toilet paper as it is suitably divided into equally sized sheets.
This time we say that one leaf is equal to the distance from Mercury. Unfortunately, this is on a different scale than the size of the planets – if they were on the same scale, Neptune would be 7km away!
Then open the toilet paper, count the sheets until you get the right number and place the planet on it. Isn’t it impressive how much space there is between them?
And that’s not even the entire solar system. If you included the Oort cloud in this model, you would need about 250,000 sheets of toilet paper.
5. Why are there seasons on Earth?
You will need a lamp (for the sun), an orange (for the earth) and a stick.
Due to the tilt of the Earth’s axis of rotation, there are four seasons on Earth. But why does the slope affect the weather?
Glue an orange to a stick and then draw the equator of the orange. As with the darkness experiment, find a dark room and hold the orange up to the light so that half of it is illuminated.
Instead of keeping the stick vertical, tilt it so that it is at about the same angle to the Earth’s axis of rotation, which is 23.5°.
Now let’s take a closer look at how this angle affects the Earth’s solar radiation. At point A, the tip of the rod points towards the lamp.
In the northern hemisphere, there is more sunlight, which in turn receives more energy and heats up. The north experiences summer while the south experiences winter.
We have exactly the opposite situation when our earth is on the other side of the lamp (at point C). At points B and D, the rod is directed neither to the side nor to the lamp – both hemispheres are illuminated equally. These points are spring and autumn.
6. Why do eclipses happen?
You will need: a lamp, a smaller sphere (for the moon) and a larger sphere (for the earth).
One of the most amazing astronomical observations we can observe is a solar eclipse. But how does that happen?
As the moon orbits our planet, it sometimes moves between the earth and the sun, casting a shadow.This experiment shows how it works.
Find a dark room and light the lamp. Then place the “Earth” a few meters away so that half of it is lit. Hold the “Moon” about 20 cm above the illuminated side of the “Earth” so that it casts a shadow on the surface.
It will only be a small shadow, which is why a solar eclipse can only be observed within a small corridor on Earth, which is determined by the size of the shadow and the rotation of our planet.
The same method can be used to view lunar eclipses.To do this, “Sun”, “Earth” and “Moon” must be aligned in such a way that the shadow of the earth falls on the moon and a lunar eclipse occurs.
You can modify this experiment even further: what happens if the “moon” doesn’t completely cover the sun or the earth’s shadow doesn’t completely fall on the lunar disc?
These experiments show what happens during a partial solar eclipse when the shadow falls just over the planet’s edge.
