This category contains questions and answers about mathematics, chemistry, astronomy and physics.

What phenomenon is caused by the refraction and reflection of light passing through water droplets?

Placing a blanket over a fire extinguishes it by robbing the flame of what gas?

What renowned scientist's lab books were once kept in lead-lined boxes because they were radioactive?

The 16th-century Italian scientist Gabriele Falloppio is famous for his work in what field?

The "heat index" is a weather indicator that takes into account air temperature and what other factor?

The Scoville scale is used to measure what?

The name of what basic component in nature is derived from a Greek term meaning "indivisible"?

When their perimeters are of equal length, which of these shapes always has the largest area?

When the number 4 is multiplied by its reciprocal, what is the product?

What number follows 8 in the Fibonacci sequence 1, 1, 2, 3, 5, 8?

The moon is roughly how far from the Earth?

The product of two negative numbers is always what?

The lowest possible temperature, 0 Kelvin is commonly known as what?

On the Fahrenheit scale, 98.6 degrees is generally considered to be what?

What gaseous element makes up about 70 percent of the mass of the Sun?

The unit a 'cable length' is named after the length of a ship's anchor cable in the Age of Sail. What is an international cable length?

Earth's inner core is thought to consist mainly of iron and another metal. Which?

Which chemical element is by mass the third-most abundant element in the universe after hydrogen and helium?

This chemical element was discovered independently by Carl Wilhelm Scheele in 1773 and Joseph Priestley in 1774. The latter is often given priority because his work was published first. Which element?

7 x 6 = ?

8 x 6 = ?

6 x 4 = ?

9 x 9 = ?

8 x 9 = ?

6 x 5 = ?

7 x 7 = ?

9 x 8 = ?

7 x 9 = ?

6 x 7 = ?

9 x 7 = ?

9 x 3 = ?

9 x 4 = ?

8 x 8 = ?

8 x 5 = ?

3 x 7 = ?

3 x 9 = ?

8 x 7 = ?

4 x 4 = ?

5 x 6 = ?

5 x 7 = ?

5 x 8 = ?

5 x 9 = ?

4 x 8 = ?

9 x 2 = ?

8 x 4 = ?

9 x 6 = ?

5 x 4 = ?

6 x 6 = ?

2 x 9 = ?

7 x 8 = ?