Science Project Ideas for Kids

I need to make a correction and update the answer for this question. I incorrectly used the term phosphorescence for the glow of a scorpion–It is actually an example of fluorescence.

Question: Why do scorpions glow under a black light?

Answers:

The scorpion has phosphors in its exoskeleton.

1. A  phosphor is a term used to describe any substance that absorbs  a form of high-energy light and releases it in the form of lower energy light.

2. Black lights give off  Ultraviolet A, which is a type of high-energy. When the phosphor in the exoskeleton of a scorpion absorbs UVA, some of the electrons in the atoms making up the phosphor  become excited. This means that the electrons move further way from the nucleus. These excited electrons quickly release energy and return to their normal position, called ground state. The released energy is in the form of lower-energy visible light. Thus the scorpion glows as shown under a black light.

The glow from the scorpion is an example of photoluminescence. WOW! That is a big word, but it is actually easy and certainly fun to experiment with. Let’s take the word apart–photo is a prefix for light and luminescence is any cold light–light from something that is not hot. OK, if we put the word parts back together we have a cold light produced by some light source. This source excited electrons, and then they release visible light when they “calm down” or return to ground state.

The scorpion only glows during the time it is exposed to black light (UVA). This type of luminescence is called fluorescence.

Some things continue to glow after the light energy source is removed. This type of luminescence is called phosphorescence. These materials can store the absorbed light energy and release it slowly. Examples are glow-in-the dark toys. Also solar active materials, such as beads that change colors when exposed to sunlight or black light.

Bananas grow in bunches. Like other fruit, ethylene gas produced by ripening bananas speeds up the ripening process.

I read that leaving  bananas attached to their stem  speeds up their ripening process.  Is this really true? How could you find out?

This would make a great science project. Just make sure that all the bananas being tested are at the same stage of ripening. Also, since bananas connected to the stem touch each other, you would have to place separated bananas in a similar position.

For more information about fruit ripening, see Fruit Ripening.

The far side of the Moon is the side that never faces Earth, and it is not always dark. In fact, a little more than half of the Moon’s surface is lit all the time. From Earth, you can only see about half of the Moon’s surface and it is always the same. So how does the Moon orbit around Earth so that only one side faces Earth?

The answer to this questions may be easier to understand by doing a simple investigation. For details, see  MOON: MOVEMENTS

Solar System Scale Model

A. Planetary Distances: A scale of 1 cm:5×10⁶ km (1 cm : 5 million km) can be used to make a model for for planetary distances.

To calculate the model distance of planets to the sun divide the actual distance by 5 million km. The answer will be measured in centimeters, cm.

For example: actual distance of Mercury to the Sun =57 million km

model distance =57 million km ÷ 5 million km = 11.6 cm

For information about planet distances from the Sun and planet diameters, check out
Kids Astronomy.com.

B. Planetary Sizes: A scale for comparing planetary sizes is 1 cm:2×10³ km (1 cm: 2 thousand km).

To calculate models of planets, divide the actual diameter of each planet measured in kilometers by 2×10³ km.

Question:

Using the scale that 1 cm = 2,000 km, what is the scale for the Earth and its Moon?

Answer:

1. The diameter of the Earth is 12,755 km.

12,755 km ÷ 2,000 cm/km = 6.377 cm or 6.4 cm

The scale diameter of the Earth would be 6.4 cm

2. The diameter of the Moon is about 1/4 the diameter of Earth.

6.4 cm ÷ 4 = 1.6 cm

Trying to produce a scale model of each part of the solar system is difficult. While the scale of
1 cm: 2 thousand km
works well with comparing the planets, the moons for the planets would be very small.